Introduction
Eckener Point (64° 26′S; 61° 36′W) lies on the northeast side of the entrance to Charlotte Bay and southeast of Murray Island, on the west coast of Graham Land, Antarctic Peninsula (Fig. 1). Data from a 1987 census (Woehler Reference Woehler1993) show 40 breeding pairs of chinstrap penguins Pygoscelis antarctica at the site. An unpublished report of 180 nests of blue-eyed cormorant Phalacrocorax atriceps/bransfieldensis (S Poncet, personal communication, 2004) in 1983 is the only other ornithological record for the site. Here we report on the results of a brief survey conducted to document the breeding seabirds for this locality. Suitable ice-free sites on the Antarctic Peninsula are limited, and Eckener Point, though small, provides nesting habitat for a high number of avian species. Plant and lichen diversity also appears unusually high.
Fig. 1. Map of Eckener Point region, based on HM Hydrographic Office Chart 3566. Contour interval is 1000 m. The two arrows indicate the extent of the survey conducted on 13 December 2006.
Methods
Between 0545 and 0630 local (UTC-2) on 13 Dec 2006, the authors conducted a brief (45 minute) survey of Eckener Point from a small boat approximately 100 m offshore. Digital and film images were taken, and the ice-free areas searched with binoculars. Breeding colonies and nest sites were mapped, and all observations of non-breeding birds noted. A brief (approximately 5 min) landing was made to count the two chinstrap penguin colonies at the site.
Results
At least seven species of birds breed or are likely to breed at Eckener Point (Table 1). This small (approximately 1 ha of ice-free terrain) locality comprises a series of three steep, vegetated bluffs facing northwest to north (Fig. 1). Adjacent ice-free areas appear too steep and uniform to provide nesting habitat for breeding birds. Eckener Point supports a diverse community of vegetation consisting of mosses and foliose and crustose lichens, and is apparently similar in diversity to the nearby Cuverville Island, one of the most vegetatively diverse sites in Antarctica (de Leeuw Reference de Leeuw, Aptroot and van Zanten1998).
Table 1. Estimated breeding populations and non-breeding seabirds recorded at Eckener Point, 13 December 2006.
Breeding seabird species
We documented two small colonies of chinstrap penguins, one of 10 and the other of 20 nests. No other species of penguins were breeding at Eckener Point during our survey. There were 21 kelp gull nests Larus dominicanus evident, with more than 40 adult gulls in view during the visit (both flying and sitting birds). A further 16 nests were observed on a steep vegetated slope approximately 400 m eastward, between Eckener Point and the adjacent unnamed glacier. We observed four pairs of skuas at the site and recorded a total of eight additional individuals whose spacing on the bluffs suggested that they were occupying four more territories. The only pair observed clearly enough to identify taxonomically was of a sub-Antarctic skua (Catharacta lonnbergi) and hybrid sub-Antarctic/South Polar (C. maccormicki) skua; the remaining birds were too distant to confirm their taxonomic identity. Six Antarctic terns Sterna vittata (unknown subspecies/race) were observed. Three were sitting in a manner to suggest nesting, while the remaining three birds were flying overhead and were assumed to be nesting locally. Two colonies of blue-eyed cormorants were present. One colony on the ridge of a bluff comprised 41 nests, while a second colony of 28 nests was sited within a small gully to the west of the ridge. Many nests contained large chicks (estimated at 3 to 5 weeks old) and approximately 20 immature cormorants were roosting adjacent to the nesting areas. Based on the area of rock discoloured by cormorant guano, and on numbers from the single previous recorded site visit, the colony has been larger in the past compared to the area and numbers documented during this survey
Unconfirmed breeding species
A number of other birds were present during the visit, but their breeding status was unconfirmed. Three individual gentoo penguins P. papua were roosting adjacent to the smaller chinstrap penguin colony; there was no evidence of any nesting attempt by these birds. Two Wilson's storm petrels Oceanites oceanicus flew low over the scree slopes of the bluffs. Suitable nesting habitat was present and it is likely that this is a breeding species for the site. One snowy sheathbill Chionis major was observed foraging among the cormorant nests; it is also probable that at least one pair of sheathbills nest at Eckener Point
Discussion
Comparison with previous data
Woehler (Reference Woehler1993) reported 40 chinstrap penguin nests (count accuracy: N3–4) from a survey conducted in 1987. An accuracy estimate of N3–4 indicates an error of ±10–15% for the datum. The present results do not show a change in this population. In contrast, the number of blue-eyed shags at this site is approximately one-third that recorded during an earlier survey. This decrease concurs with an apparent region wide trend for the species, with marked decreasing trends at most sites and populations disappearing altogether at others (Naveen and others Reference Naveen, Forrest, Dagit, Blight, Trivelpiece and Trivelpiece2000; Casaux and Barrera-Oro Reference Casaux and Barrera-Oro2006; Lynch and others Reference Lynch, Naveen and Fagan2008)
New data
Previous data for this locality only describe populations of blue-eyed shags and chinstrap penguins. Eckener Point supports a greater number of seabird species than previously recorded, and while the northwest Antarctic Peninsula is a relatively well surveyed part of Antarctica, documentation of new sites with aggregations of nesting birds is increasingly infrequent. Our decision to survey Eckener Point was prompted by its nomination as an important bird area (IBA) for blue-eyed shags due to the high breeding population previously recorded there. The pronounced decrease in numbers of shags nesting at this site underscores the importance of monitoring populations of this species in the region, and reinforces the need to conduct a full region wide inventory of this species.
Acknowledgements
We thank expedition staff and the officers and crew of the MV National Geographic Endeavour for their assistance and support. The survey is a contribution to the Antarctic Site Inventory, administered by Oceanites, Inc. Two anonymous reviewers are thanked for their comments.
